Refactor shadow rendering logic.

Source/core/rendering/EllipsisBox.cpp

 /**
  * Copyright (C) 2003, 2006 Apple Computer, Inc.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Library General Public License for more details.
  *
  * You should have received a copy of the GNU Library General Public License
  * along with this library; see the file COPYING.LIB.  If not, write to
  * the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
  * Boston, MA 02110-1301, USA.
  */
 
 #include "config.h"
 #include "core/rendering/EllipsisBox.h"
 
 #include "core/dom/Document.h"
+#include "core/platform/graphics/DrawLooper.h"
 #include "core/platform/graphics/Font.h"
 #include "core/platform/graphics/GraphicsContextStateSaver.h"
 #include "core/platform/graphics/TextRun.h"
 #include "core/rendering/HitTestResult.h"
 #include "core/rendering/InlineTextBox.h"
 #include "core/rendering/PaintInfo.h"
 #include "core/rendering/RenderBlock.h"
 #include "core/rendering/RootInlineBox.h"
+#include "core/rendering/style/ShadowData.h"
+#include "wtf/Vector.h"
 
 #include <algorithm>
 
 namespace WebCore {
 
 void EllipsisBox::paint(PaintInfo& paintInfo, const LayoutPoint& paintOffset, LayoutUnit lineTop, LayoutUnit lineBottom)
 {
     GraphicsContext* context = paintInfo.context;
     RenderStyle* style = m_renderer->style(isFirstLineStyle());
     Color textColor = style->visitedDependentColor(CSSPropertyWebkitTextFillColor);
     if (textColor != context->fillColor())
         context->setFillColor(textColor, style->colorSpace());
 
     Color actualTextColor = textColor;
     const Font& font = style->font();
     if (selectionState() != RenderObject::SelectionNone) {
         paintSelection(context, paintOffset, style, font);
 
         // Select the correct color for painting the text.
         Color foreground = paintInfo.forceBlackText() ? Color::black : renderer()->selectionForegroundColor();
         if (foreground.isValid() && foreground != textColor)
             actualTextColor = foreground;
     }
 
+    const ShadowData* shadow = style->textShadow();
+    bool hasShadow = !!shadow;
+    if (hasShadow) {
+        // FIXME: it would be better if we could get the shadows top-to-bottom from the style.
+        Vector<const ShadowData*, 4> shadows;
+        do {
+            shadows.append(shadow);
+        } while (shadow = shadow->next());
+
+        DrawLooper drawLooper;
+        drawLooper.addUnmodifiedContent();
+        for (int i = shadows.size() - 1; i >= 0; i--) {
+            shadow = shadows[i];
+            int shadowX = isHorizontal() ? shadow->x() : shadow->y();
+            int shadowY = isHorizontal() ? shadow->y() : -shadow->x();
+            FloatSize offset(shadowX, shadowY);
+            drawLooper.addShadow(offset, shadow->blur(), shadow->color(),
+                DrawLooper::ShadowRespectsTransforms, DrawLooper::ShadowIgnoresAlpha);
+        }
+        context->setDrawLooper(drawLooper);
+    }
+
     // FIXME: Why is this always LTR? Fix by passing correct text run flags below.
-    const ShadowData* shadow = style->textShadow();
     FloatPoint boxOrigin(paintOffset);
     boxOrigin.move(x(), y());
     FloatRect boxRect(boxOrigin, LayoutSize(logicalWidth(), logicalHeight()));
     FloatPoint textOrigin(boxOrigin.x(), boxOrigin.y() + style->fontMetrics().ascent());
     TextRun textRun = RenderBlock::constructTextRun(renderer(), font, m_str, style, TextRun::AllowTrailingExpansion);
     TextRunPaintInfo textRunPaintInfo(textRun);
     textRunPaintInfo.bounds = FloatRect(boxOrigin, FloatSize(logicalWidth(), logicalHeight()));
-
-    bool opaque = actualTextColor.alpha() == 255;
-    if (!opaque)
-        context->setFillColor(Color::black, style->colorSpace());
-    else
-        context->setFillColor(actualTextColor, style->colorSpace());
-
-    do {
-        IntSize extraOffset;
-        if (shadow) {
-            FloatSize shadowOffset(shadow->x(), shadow->y());
-            if (shadow->next() || !opaque) {
-                FloatRect shadowRect(boxRect);
-                shadowRect.inflate(shadow->blur());
-                shadowRect.move(shadowOffset);
-                context->save();
-                context->clip(shadowRect);
-                extraOffset = IntSize(0, 2 * boxRect.height() + std::max(0.0f, shadowOffset.height()) + shadow->blur());
-                shadowOffset -= extraOffset;
-            }
-            context->setShadow(shadowOffset, shadow->blur(), shadow->color(), style->colorSpace());
-        } else if (!opaque)
-            context->setFillColor(actualTextColor, style->colorSpace());
-
-        context->drawText(font, textRunPaintInfo, textOrigin + extraOffset);
-
-        if (!shadow)
-            break;
-
-        if (shadow->next() || !opaque)
-            context->restore();
-        else
-            context->clearShadow();
-
-        shadow = shadow->next();
-    } while (shadow || !opaque);
+    context->drawText(font, textRunPaintInfo, textOrigin);
 
     // Restore the regular fill color.
     if (textColor != context->fillColor())
         context->setFillColor(textColor, style->colorSpace());
 
+    if (hasShadow)
+        context->clearDrawLooper();
+
     paintMarkupBox(paintInfo, paintOffset, lineTop, lineBottom, style);
 }
 
 InlineBox* EllipsisBox::markupBox() const
 {
     if (!m_shouldPaintMarkupBox || !m_renderer->isRenderBlock())
         return 0;
 
     RenderBlock* block = toRenderBlock(m_renderer);
     RootInlineBox* lastLine = block->lineAtIndex(block->lineCount() - 1);
@@ skipping 70 matching lines @@
     if (visibleToHitTestRequest(request) && boundsRect.intersects(HitTestLocation::rectForPoint(locationInContainer.point(), 0, 0, 0, 0))) {
         renderer()->updateHitTestResult(result, locationInContainer.point() - toLayoutSize(adjustedLocation));
         if (!result.addNodeToRectBasedTestResult(renderer()->node(), request, locationInContainer, boundsRect))
             return true;
     }
 
     return false;
 }
 
 } // namespace WebCore